Today is October 4th．It's World Animal Day．Gina  and her sister Sally go to the____early．They want to do some things for the____there．In the south of the zoo，Gina finds an elephant．Its____ are kind of dirty．Gina and Sally get some____and clean them．After that they get some food for this elephant．After the elephant eats the food，the two girls take a photo with it．Then they play with it．

    This elephant is____．It can draw．It can play soccer,too．Gina and Sally like it very much．Gina and Sally play with it for a long time．They have a great time in the zoo．

将一把钢尺紧按在桌面上，一端伸出桌面适当的长度，拨动钢尺，就可听到钢尺振动发出的声音。逐渐增加钢尺伸出桌面的长度，钢尺振动发出声音的音调会逐渐变____ 。当钢尺伸出桌面超过一定长度时，虽然用同样的力拨动钢尺振动，却听不到声音，这是由于____ 。

下面有关我国海洋国土的叙述，不正确的是（　　）